The invention relates to an integrating time detector for use in a photographic apparatus.
An integrating circuit is used, for example, in a photometric circuit of a photographic apparatus, in particular, in a direct photometric circuit. The integrating circuit is adapted to integrate a photocurrent which is produced by a photoelectric transducer element in response to the incidence of reflected light from an object being photographed thereon in order to determine an exposure period which corresponds to the light from the object. Such circuit suffers from the disadvantage that the integration cannot be performed over an increased length of time since the integrating period is limited by the characteristic of an integrating capacitor used, for example, the leakage current thereof. When the integrating circuit is used in a photographic camera, this means that the combination cannot allow an exposure period for the camera which has an increased value. On the other hand, when such integrating circuit is used in a situation involving a low level of illuminance as when taking a picture with a microscope, an inconvenience is experienced that it takes a long integrating time.